Sewing machine housing



NOV. 10, G. STEHR SEWING MACHINE HOUSING Filed Feb. 14, 1951 Inventor GE ORG STE HR BY KMM, M

ATT'YS Patented Nov. 10, 1953 UNITED STATES PATENT OFFICE SEWING MACHINE HOUSING Georg Stehr, Kappeln-Schlei, Germany Application February 14, 1951, Serial No. 210,814

Claims.

My invention relates to sewing machines, preferably to those for household purposes, and more particularly to the machinery housing structure that supports and encloses the mechanism and transmission means of such machines.

In the conventional sewing machines, a hollow pedestal rises vertically from the work-table base of the machine and carries a horizontally extending hollow arm whose end merges with a head structure suspended above the pressure plate of the machine. The horizontal arm is traversed by the shaft for driving the vertically movable machinery parts housed in the head structure, such as the needle bar, thread feed lever, or the vertical presser rod, etc. In the known machines, this drive shaft carries also a drivin sheave and a fly wheel at the shaft end remote from the head structure and outside the machinery housing. The pedestal is usually traversed by a bevel gearing, the pitman rod of an eccentric and the like transmission means which extend downwardly below the work-table plate to actuate the drive mechanisms of the loop taker and cloth feed devices. From this universally customary build-up of the sewing machinery, the above-mentioned conventional shape of the appertaining machinery housing resulted as a logical consequence. Indeed, this housing design, though slightly modified in the various makes, is a common characteristic of all sewing machines now on the market.

My invention stems from the recognition that the conventional and universally accepted construction of sewin machines, especially that of the machinery housing structure, with its sharpedged parts, protuberances and other irregularities, leaves much to be desired and is out of harmony with modern requirements. It is therefore an object of my invention to devise a sewing machine, particularly a machinery housing structure, of a simplified design and a smooth exterior shape, free of projecting and sharp-edged elements which housing, however, is readily producible by ordinary manufacturin methods.

In conjunction with the foregoing object, my invention aims at securing a good sewing performance with the aid of a much smaller number of machine elements than needed in the conventional machines.

To this end and in accordance with a feature of my invention the box-shaped base structure of a sewing machine is equipped with an integral hollow arm of arcuate exterior shape which rises from the work-table surface of the machine base and arches back to that surface to a point above 2 the stitching plate of the machine. The arm has a smooth or streamlined outer surface and a rounded cross section which decreases from the foot toward the free end of the arm.

According to another feature of the invention, an arcuate lever pivotally mounted on, and driven from within, the machine base extends through the hollow arm to hold the sewing needle at its swinging end.

These and more specific features of the invention, set forth with particularity in the claims annexed hereto, are apparent from the embodiment illustrated by way of example on the accompanying drawing, in which Figure 1 is a sectional side view and Figure 2 a top view of a household-type sewin machine according to the invention.

According to the drawing, the housing of the machine comprises a base I shaped as a flat and rectangular box structure open at its bottom. Contrary to the conventional sewing machines, the drive and main shaft of the machine are disposed within this box-shaped base. Integral with the base I is an arcuate arm 4 whose transitory foot portion has a rectangular but well rounded cross section smoothly merging with the worktable top I of the base. The arm 4 extends in an approximately oval arch from its junction with the base I to above the pressure plate -5. The sewing needle 1 and the appertaining needleholder project from the end 6 of arm 4 downwardly, and the needle traverses a bore or marginal recess of the plate 5 in the customary manner. The arm 4 tapers from its foot toward the end 6. As apparent from the drawing, the degree of tapering in the top view is less than in the side view. This particular design is favorable for obtaining the space necessary for mounting the presser foot 8 behind the needle I on the end of arm 4. In addition, the unequal tapering in vertical and horizontal directions has also the result of improving the harmony of appearance of the arm structure. The exterior surface of arm t is completely smooth. All projections and such other protuberances as are required in the known machines by the appertaining operating mechanisms are eliminated.

It will be understood that such a simplified and appearance-improved housing structure according to the invention does not lend itself readily to being used with old-type operating mechanisms, but requires a mutual adaptation or correlated designs of machinery housing and enclosed mechanisms. In this respect, however, a housin structure according to the invention is 3 especially well compatibl with modern attempts at simplifying the machines as to mechanism and manufacture, as will be recognized from the following.

In the illustrated example, the needle I is mounted on an arcuate lever 3 which extends through the hollow of arm 4 and is pivoted at 3' in the base I near its junction with arm 4. The main drive shaft 9 of the machine is located in the base structure and is connected with the needle lever 3 by means of an eccentric 9' and an appertaining link Ill. The engagement of link it) with eccentric 9 permits the angular movements of link ll] relative to shaft 9 necessary for the desired operation. The drive motor, preferably an electric motor (not illustrated), is also mounted within the base I. A thread feed lever i l is pivoted in the arm 4 about a horizontal pivot pin l2 and is pivotally linked to lever 4 by a link bar l3. Only the eye portion of lever l! projects out of arm 4. The thread is guided along arm 4, while the pin for the thread spool is preferably mounted at a place completely covered by the work-table plate, so that the spool of thread remains invisible.

As shown, a straight needle 1 is applicable. To keep the lateral. needle movements at a minimum, the pivot 3' lies in a horizontal plane passing approximately through the center of the cloth-penetrating portion of the needle. In the illustrated machine, the lateral needle movements are within negligible limits.

I claim:

1. A sewing machine mechanism, comprising a box-shaped hollow base structure having a work-table top surface and having a stitching plate on said surface, a hollow arm integral with said base structure and having an arcuate exterior shape in a vertical plane, said arm rising from said surface at a place remote from said plate and arching downwardly back toward said surface to above said plate, said arm having its hollow merging with that of said base structure and having exteriorly along its entire length a continuous and substantially uniform curvature of its upper and lower contours within said vertical plane, a drive shaft journalled within said base structure, and needle-operating mechanism means extending through said arm and being connected with said shaft to be actuated thereby.

2. In a sewing machine according to claim 1, said hollow arm having a rounded exterior corner at the place where said arm is joined with said base structure so that said arm gradually and continuously broadens toward its junction with said base structure, and said arm being continuously tapered along its arcuate length from said place to the opposite end of said arm.

3. In a sewing machine according to claim 2, said arm having a substantially rectangular cross section with rounded corners, and the amount of tapering along said arm being less in the horizontal plane than in the vertical plane of said arm.

4. A sewing machine, comprising a housing structure having a hollow table-top base and a hollow arcuate arm, a horizontal stitching plate on said base, said arm being integral with said base at a place horizontally spaced from said stitching place and arching from said base upwardly and back downwardly to a point above said stitching plate, a drive shaft revolvable in said base, a lever reciprocably pivoted to said base near the merger place of said base and said arm, said lever being arcuate and extending through said arm toward said location, needle holding means mounted on said lever at said location. and reciprocating transmission means linking said lever with said shaft.

5. In a sewing machine according to claim 1, said mechanism means comprising an arcuate lever extending through said arm and having a pivot in said base structure near the merging place of said base structure and said arm, said pivot having an axis in a radial plane of said shaft, an eccentric mounted on said shaft, and a link engaging said eccentric and pivotally joined with said lever to reciprocate said lever about said pivot, said link being angularly movable relative to said eccentric in an axial plane of said shaft.

GEORG STEHR.

References Cited in the file of this patent UNITED STATES PATENTS Number 

